Diverse manifestations of insolation forcing of environmental changes during the middle Piacenzian

2021 ◽  
Author(s):  
Peng Gao ◽  
Junsheng Nie
Keyword(s):  
High Resolution ◽  
Asian Monsoon ◽  
Environmental Changes ◽  
East Asian Monsoon ◽  
East Asian ◽  
Ice Volume ◽  
Global Ice Volume ◽  
Direct Forcing ◽  
Insolation Forcing ◽  
Higher Sensitivity

<p>The middle Piacenzian period is the closest sustained warm interval and a possible analog to the future climate. It is well known that global ice volume exhibits dominant 41-kyr cyclicities. However, high resolution terrestrial paleoenvironmental records are scare. Here we present a 3.6 kyr terrestrial environmental variation record from Teruel Basin of Spain and compare the results with the East Asian monsoon records. The Spain results show dominant 41-kyr cycles during the early Piacenzian (3.3-3.15 Ma) when eccentricity was at minimum, but the 41-kyr cycles weakens during the late Piacenzian 3.15-2.95 Ma when eccentricity got increased, suggesting direct forcing by insolation. This pattern is different from the monsoonal records from China, which demonstrates persistent 20-kyr cycles during the entire middle Piacenzian. The strong 41-kyr cycles in westerly region during the early Piacenzian may originate from its higher latitude and higher sensitivity to insolation gradient forcing.</p>

scholarly journals High Resolution Late-holocene Terrestrial Biomarkers Records in Southern Continental Shelf Area of the Korean Peninsula: Climate and Marine Environmental Implications During the Last 5 Kyr

2020 ◽  
Author(s):  
Sangmin Hyun ◽  
Nayeon Kang ◽  
Jin Hyung Cho
Keyword(s):  
High Resolution ◽  
Continental Shelf ◽  
Korean Peninsula ◽  
Environmental Changes ◽  
East Asian Monsoon ◽  
East Asian ◽  
Average Chain Length ◽  
Shelf Area ◽  
Environmental Implications ◽  
Marine Environmental

Abstract High-resolution records for carbon isotopes of organic matter and n-alkane compounds were investigated in two gravity cores (SJP15-2 and SJP15-4) taken from the southern continental shelf of the Korean peninsula to evaluate the variation in influxes of terrestrial organic compounds and their linkage to paleoclimate and marine environmental changes since the last 5 kyr. The total organic carbon contents were < 1%, and the carbon isotope(d13Corg) ratio ranged from approximately −21‰ to -22‰ and, they did not highly fluctuate throughout the two cores. However, the vertical distributions of total terrestrial biomarkers, long-chain n-alkanes (nC25-35), and individual n-alkane compounds exhibited distinctive fluctuations. There are three switching points that discriminate patterns of excursion and distribution at ca. 4.5 ka, 3.0 ka, and 1.8 ka. Several n-alkane combined indices such as average chain length (ACL), carbon preference index (CPI), and paleovegetation index (Paq), were coincident with these switching points, implying that the supply of terrestrial biomarkers was strongly associated with environmental changes at the source area. In particular, the ratios of nC31/nC27 and nC31/nC29 show coincident excursion pattern with lower ratio between 3.0 ka and 1.8 ka, implying that this short-term event-like record (STER) was associated with wetter climate conditions, and thus paleovegetation and paleoclimate variation. Comparison with previous data of the detrital quartz from the East China Sea and aeolian dust in the Cheju (Jeju) Island, South Korea, and Dongge cave oxygen isotope records indicates strong synchronicity with those switching points, suggesting that paleoclimate system of the East Asian region may have influenced the sediment records of study area since the last 5 kyr. Therefore, our high-resolution n-alkane data are very useful for reconstructing past climatic records, and East Asian monsoon and regional records could be associated with the paleoclimate variations of the study area.

Variation of Rb/Sr Ratios in the Loess-Paleosol Sequences of Central China during the Last 130,000 Years and Their Implications for Monsoon Paleoclimatology

1999 ◽  
Vol 51 (3) ◽  
pp. 215-219 ◽  
Author(s):  
Jun Chen ◽  
Zhisheng An ◽  
John Head
Keyword(s):  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Central China ◽  
Last Interglacial ◽  
Ice Volume ◽  
Global Ice Volume ◽  
Asian Summer ◽  
Monsoon Strength ◽  
High Degree

AbstractRb, Sr, and magnetic susceptibility have been measured in the last interglacial–glacial loess profiles at Luochuan and Huanxian, central China. A high degree of similarity between the parameters in both profiles suggests that variations of Rb/Sr ratios in the sequence can be regarded as an indicator of East Asian summer monsoon strength. Matching the Rb/Sr record with the SPECMAP δ18O curve suggests that the Rb/Sr ratio responds sensitively to changes of the East Asian monsoon induced by global ice-volume variation.

scholarly journals East Asian monsoon during the past 10,000 years recorded by grain size of Yangtze River delta

2021 ◽  
Vol 13 (1) ◽  
pp. 505-516
Author(s):  
Xiaohui Wang ◽  
Longsheng Wang ◽  
Shouyun Hu ◽  
Ge Yu ◽  
Qing Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Yangtze River ◽  
Asian Monsoon ◽  
Environmental Changes ◽  
East Asian Monsoon ◽  
East Asian ◽  
Yangtze River Delta ◽  
River Delta ◽  
The Yangtze River ◽  
The Yangtze River Delta

Abstract Paleoenvironmental research is critical for understanding delta evolution processes and managing delta sustainability, particularly for delta experiencing significant recent fluvial sediment discharge. Based on other previously reported optically stimulated luminescence (OSL) data, Holocene environmental changes of the Yangtze River delta in response to climate fluctuations and human activities were reviewed on the basis of grain-size analyses of core YZ07. The results of grain-size and end-member analysis (EMA) provide a detailed history of East Asian monsoon variability and environmental changes since ∼10,000 cal year B.P. The lower median values (Md) and sand content reflect relatively cool and dry climate conditions between 10,000 and 9,570 cal year B.P. During the early Holocene (9,570–7,630 cal year B.P.), the highest Md values and sand contents and the lowest end member 2 (EM2) contents suggest the Holocene transgression. The increased Md values and sand contents indicate that the climate conditions were warm and wet during the mid-Holocene thermal optimum. From 4,690 to 4,150 cal year B.P., the climate was cool and dry, corresponding to the cool event, as indicated by the finer grain size. Subsequently, between 4,150 and 2,850 cal year B.P., the grain size derived from the Md value and sand content increased, which reflect a wet and warm episode. The climate, which shifted from warm and wet to cool and dry between 2,850 and 1,020 cal year B.P., may have caused a reduction in the sand contents and Md values. After 1,020 cal year B.P., the lowest values of Md and Standard deviation (Sd) and the highest contents of EM2 and clay suggest that the Yangtze River delta has been severely affected by anthropogenic activity. The variability of the East Asian monsoon intensity in the Yangtze River delta strongly correlates with other East Asian monsoon paleoclimate records in China. These results are important for investigations into the interactions between regional systems and global change in monsoonal climatic regions and can provide an example of the evolution of a large scale geomorphic feature resulting from river-sea interaction.

scholarly journals East Asian monsoon climate during the Late Pleistocene: high-resolution sediment records from the South China Sea

1999 ◽  
Vol 156 (1-4) ◽  
pp. 245-284 ◽  
Author(s):  
L Wang ◽  
M Sarnthein ◽  
H Erlenkeuser ◽  
J Grimalt ◽  
P Grootes ◽  
...  
Keyword(s):  
High Resolution ◽  
South China Sea ◽  
Late Pleistocene ◽  
South China ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
The South China Sea ◽  
Monsoon Climate ◽  
Sediment Records

East Asian monsoon variability since the Mid-Holocene recorded in a high-resolution, absolute-dated aragonite speleothem from eastern China

2008 ◽  
Vol 275 (3-4) ◽  
pp. 296-307 ◽  
Author(s):  
Jason Cosford ◽  
Hairuo Qing ◽  
Bruce Eglington ◽  
Dave Mattey ◽  
Daoxiang Yuan ◽  
...  
Keyword(s):  
High Resolution ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Eastern China ◽  
Monsoon Variability
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